caroline a. cantley for advanced ligo suspension team / university of glasgow /geo600 group
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Update on Advanced LIGO suspension design and technology development
towards the quad noise prototype
Caroline A. Cantleyfor Advanced LIGO Suspension Team / University of
Glasgow /GEO600 Group
LSC Meeting, LLO March 2005
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Advanced LIGO suspension team LIGO Lab :
CIT: H. Armandula, M. Barton, D. Coyne, J. Heefner, M. Mageswaran, K. Mailand, J. Romie, C. Torrie. MIT: P. Fritschel, K. Mason, R. Mittleman, L. Ruet, D. Shoemaker LHO: B. Bland, D. Cook LLO: J. Hanson, H. Overmier, O. Spjeld, G. Traylor
GEO600: Glasgow: G. Cagnoli, C. Cantley, A. Cumming, D. Crooks, E. Elliffe, A. Grant, A. Heptonstall, J. Hough, R. Jones, I. Martin, M. Perreur-Lloyd, M. Plissi, D. Robertson, S. Rowan, K. Strain, P. Sneddon, H. Ward Universitat Hannover: H. Lueck
Stanford University: N. Robertson (also GEO/Glasgow)
Rutherford Appleton Laboratory (CCLRC): J. Greenhalgh, T. Hayler, I. Wilmut
University of Birmingham: S. Aston, D. Hoyland, C. Speake, A. Vecchio, M. Cruise
Strathclyde University: N. Lockerbie
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Quad controls prototype US in collaboration with UK First quad suspension build
Caltech May ’05 check/refine assembly &
disassembly procedure interference check matching of blade stiffness &
deflection – blade test facility (RAL)
handling of blades – blade flattener
Structural resonance testing modal frequency measurement
(Caltech) coupled dynamics (ETF
Stanford) Jun ‘05 Due to be installed LASTI
Jul’05
(CIT, Glasgow, Stanford, RAL, B’ham)
Controls prototype ETM quad suspension and
structure
Dynamic structural analysis
1st mode 90 Hztarget 100 Hz + 15%
Talks by J. Romie (next) + C. Torrie (Tues p.m.)
all metalprototype
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OSEM development Birmingham/Strathclyde with input from
Glasgow, RAL & LIGO Modified Hybrid OSEMs meet performance
requirements Good low frequency performance expected
~ 1 x 10-10 m/Hz at 1Hz~ 0.6 mm (p-p) working range
Production optimisation of Hybrid OSEM electromechanical design
Fabrication of a small quantity of prototype devices underway
Electronics & OSEM testing begins April at Birmingham
Schedule permitting, may test in quad controls prototype Talk by S. Aston (Tues p.m.)
(Aston, Cantley, Greenhalgh, Hoyland, Lockerbie, Robertson, Speake, Strain, Vecchio, Ward)
Hybrid OSEM design
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Quad noise prototype Final stage is monolithic (based
on GEO600 technology) Silica test & penultimate mass Silica ribbons Silica attachment ears
Assembly Mass catcher/assembly jig design
+ handling of 40 kg silica masses Effect of test mass material
downselect to silica Ear bond area Ribbon taper shape – flexure
positions / thermal noise Manufacturing tolerance &
alignment specifications Monolithic suspension workshop
held in Glasgow Jan 05
(Glasgow, RAL, CIT, Stanford, B’ham)
Noise prototype (silica) ETM quad suspension and upper structure (lower structure not shown here)
Mass catcher/assembly jig – formspart of lower structure
monolithic finalstage
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Optic ear development – design criteria GEO 10 kg masses (bond area 2 x 3
cm2) Design drivers
mechanical strength silicate bond thermal noise
Ear geometry/position ribbon flexure point offsets minimise peeling effect
Ideally would scale bond area to keepstress levels as per GEO
40 kg mass would require total bond area 24 cm2
But bond thermal noise is a limitation FE analysis of inhomogeneous thermal
noise associated with silicate bonds(Cagnoli, Cantley, Crooks, Elliffe, Heptonstall, Hough, Jones, P-Lloyd, Rowan)
FE model for prediction of inhomogeneous thermal noise associated with silicate bonds.Bond image: bonds are 81 nm thick.
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Limit on ear bond area due to thermal noiseSystems Design Requirement:Any technical noise source equivalent strain noise must be less than 10% of the target strain sensitivity
Baseline displacement noise (per test mass) at 100 Hz is 8 x 10-21 m/HzYields total allowable bond area of 7.1 cm2
(~ x 6 safety margin based on previous bond strength tests)Adv LIGO:4 ears each of 1.7 cm2
Strain sensitivity with 40 kg fused silica test massand beam radius 5.5cm
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Optic ear design & test Designed to reduce peeling effect and increase strength Separate ears for each ribbon (4 off total) Disadvantage: more bonding effort Strength testing: load using nail
ended wire Rigorous failure tests will be
conducted (Glasgow/CIT) Test ears fabricated end May 05
(Armandula, Cagnoli, Cantley, Crooks, Elliffe, Heptonstall, Hough, Jones, P-Lloyd, Rowan)
Silica test mass showing bonded silica attachment ears for welding the ribbons in the monolithic final stage. Inverted ears used on penultimate mass.
Load
Ribbon weldposition
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Fibres pulled up to 570 mm long avg diameter 184 m with
standard deviation 5 m Ribbon pulling commenced
move to to variable feed-pull to achieve 10:1 aspect ratio
Welding demonstrated - strength tests start soon on ribbons and welds
effect of annealing on weld strength will be investigated
Q measurements on laser pulled ribbons is in initial stages
Intensive development & characterisation period over next six months
CO2 laser pulling & welding of fibres
(Cagnoli, Cantley, Crooks, Martin, Cumming, Jones, Heptonstall, Rowan, Hough)
250 m fibre being pulled using feed & pull technique with CO2 laser
CO2 laser beam 10.6m
Silica fibre
Conical mirror
Rotating45° mirror
Motor
PULL
FEED
Silica rod
concept schematic
Fixed45° mirror
Talk by C. Cantley (Tues p.m.)
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Future work Continue to prepare for Controls Prototype
installation in LASTI (July ’05) Continue to develop noise prototype – monolithic
final stage design Test ears will be manufactured - testing will
commence at Glasgow/Caltech (June ’05) Continue to develop CO2 laser pulling & welding
machine – next phase variable feed & pull for ribbons Ribbon characterisation – strength testing & weld
strength/annealing + long term suspension of 40 kg masses
Noise prototype installation in LASTI (Aug ’06)
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